1. Field of the Invention
This invention relates to minute polymer particles having an enzyme immobilized therein and a method for the production thereof. More particularly, this invention relates to minute enzyme-occluding polymer particles having an occluded enzyme with a photo-crosslinking resin and possessing an excellent enzymatic activity and to a method for the production thereof.
2. Prior Art Statement
Heretofore, it has been known that the production of polymer particles having an enzyme immobilized therein is attained by a method which comprises dissolving the enzyme in an aqueous solution of poly(vinyl alcohol) or a derivative thereof and exposing the enzyme-containing aqueous solution to radiation thereby crosslinking the poly(vinyl alcohol) or the derivative thereof and, at the same time, immobilizing the enzyme therein [Japanese Patent Publication SHO 56(1981)-33 and Japanese Patent Publication SHO 59(1984)-13189].
Since this method requires use of radiation, however, it necessitates installation of a special apparatus and entails the possibility of the enzyme being degenerated. Thus, many problems still stand in the way of rendering this method commercially feasible.
Several methods have been known which effect the immobilization of an enzyme by the use of a photosensitive resin [Japanese Patent Public Disclosure SHO 53(1978)142594 and Japanese Patent Public Disclosure SHO 55(1980)15703].
In these methods, however, since the enzyme is immobilized in the resin which is formed in the shape of film, particles, or fibers, only the part of the enzyme exposed from the surface of the shaped article of resin actually participates in the reaction intended. As a result, the amount of enzyme which is utilized is inevitably very small as compared with the amount of enzyme immobilized.
Formerly, the inventors proposed a method for forming enzyme-occluding polymer particles preparing an enzyme-containing aqueous solution of a styrylpyridinium group-containing poly(vinyl alcohol) as a water-soluble photosensitive resin and subjecting the aqueous solution as dispersed in a hydrophobic medium to photo-crosslinking Japanese Patent Public Disclosure SHO 61(1986)-128888].
By this proposed method are obtained enzyme-occluding polymer particles 20 to 100 .mu.m in average particle diameter having the enzyme immobilized in such a state that the enzyme may manifest its function efficiently without a sacrifice of its activity.
The enzyme-occluding polymer particles obtained this proposed method, however, have a relatively large average particle diameter in the range of 20 to 100 .mu.m and are not fully satisfactory in terms of manifestation of enzymatic activity.
Further, the method itself is deficient in capacity for mass production because the aqueous solution is subjected to the photo-crosslinking as held in a stirred state and the production, therefore, is performed batchwise. Moreover, the dosage of radiation is lowered because the aqueous solution is exposed to light as held in a dispersed state and the photosensitivity is degraded because the enzyme and the resin are in a wet state.
Besides, since the particles obtained by the crosslinking are in a wet state, they must be dried prior to their use in a non-aqueous type enzymatic reaction. When they are dried, there ensues a disadvantage that they undergo conglomeration due to cohesion of adjacent particles. The particles fresh from production are wet with suspended substances adhering to their surface and, therefore, must be washed as with a solvent.